[U-Boot] [PATCH resend] armv7/ltimer: Add support for local timer on armv7 cpus

Vipin Kumar
2012-12-18T04:39:53Z

On 12/17/2012 11:20 PM, Wolfgang Denk wrote:
> Dear "Dennis Lan (dlan)",
>
> In message<CAF1ZMEcVWc3DNdcb7gQ60D-8Nx-MHOpkLs=eY0ph2w_Lgcozaw@mail.gmail.com> you wrote:
>>
>>> What would be the use of such timer support? Is there any code that
>>> actually needs it, and why does it need anything beyond the existing
>>> timer support we have?
>
>> I think vipin here is trying to provide a generic timer support for ARMV7
>> architecture,
>> which contains private(local) and global timer. It's general a good thing
>> which means we can maximize the code usage..
>
> Sorry, I don't get it. Why would we need separate global and local
> timers? And what exactly is "local" here - local to what?
>
> We don't need anything like that on other architectures - so why here?
>

Let me start afresh. There are two timer peripherals (called as local
and global) built into armv7 cores. The local timer is specific to each
processor while the global timer is common for all cores. These timers
may be initialized and used for timer operations in armv7 based SoCs

> "general a good thing" sounds like "nice to have", and this is usually
> something we don't really need, especially not in a boot loader.
>

This is nothing but a timer peripheral driver. The timer is a part of
armv7 core so it is kept in arch/arm/cpu/armv7

http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0407i/index.html

Regards
Vipin

> Best regards,
>
> Wolfgang Denk
>